﻿/*
* Copyright (c) 2010-2012 Tesla Engine Group
* 
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* 
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/

using Tesla.Bounding;
using Tesla.Math;

namespace Tesla.Scene {
    /// <summary>
    /// Utility for creating a pick query, casting a ray into a scene and finding the objects that intersect (are under the cursor).
    /// </summary>
    public static class PickingUtil {

        /// <summary>
        /// Queries the scene for valid picks.
        /// </summary>
        /// <param name="spatial">The spatial or scene to check</param>
        /// <param name="ray">The ray to use in the query</param>
        /// <param name="query">The query object that will hold the results</param>
        public static void FindPick(Spatial spatial, Ray ray, PickQuery query) {
            if(spatial == null || !spatial.SceneHints.IsPickable) {
                return;
            }

            if(spatial is IPickable) {
                query.AddPick(ray, (IPickable) spatial);
            } else if(spatial is Node) {
                Node node = spatial as Node;
                if(node.Count == 0) {
                    return;
                }
                BoundingVolume worldvol = node.WorldBounding;
                if(worldvol == null) {
                    return;
                }
                if(worldvol.Intersects(ray)) {
                    for(int i = 0; i < node.Count; i++) {
                        FindPick(node[i], ray, query);
                    }
                }
            }
        }
    }
}
